New 1:3:4-thiadiazoles



United States Patent 3,178,440 NEW 1:3:4-THIADIAZOLES Adolf Emil Siegrist, Basel, Erwin Maeder, Munchenstein, Max Duennenherger, Birsfelden, and Peter Liechti, Binningen, Switzerland, assignors to Ciba Limited, Basel, Switzerland, a company of Switzerland No Drawing. Filed Feb. 28, 1961, Ser. No. 92,133 Claims priority, application Switzerland, Mar. 1, 1960,

12 Claims. Cl. 260294.8)

The present invention provides new 1:3:4-thiadiazoles of the formula I /S\ l where R R R and n have the above meanings-with a phosphorus sulfide, preferably in the presence of a tertiary nitrogen base.

The acylhydrazines used as starting material are derived from hydrazine and at least one heterocyclic carboxylic acid and inasmuch as the radicals R R or R are aromatic, from aromatic carboxylic acids. R and R are derived from monocarboxylic acids and R is derived from a dicarboxylic acid.

Particularly suitable are those heterocylic monocarboxylic acids supplying the radicals R and/ or R which contain only one ring, for example a five-membered or sixmembered ring with preferably a single hetero atom (nitrogen, oxygen or sulfur) and 2 or 3 cyclic double bonds. Special mention among the aromatic monocarboxylic acids deserve those whichlike benzene-, diphenyland naphthalene-carboxylic acids-contain l or 2 aromatic rings. Among the aromatic dicarboxylic acids the benzene-dicarboxylic acids are especially suitable.

All carboxylic acids used in the manufacture of the acylhydrazines-and above all the monocarboxylic acids of the benzene series-may contain further, preferably non-cyclic substituent, for example halogen atoms such as bromine or chlorine, alkyl groups such as methyl, ethyl, n-propyl, isopropyl or tertiaryZ-butyl, or alkoxy groups such as methoxy or ethoxy.

From the foregoing it will be realized that it is of special advantage to use as starting material acylhydrazines of the Formula 2, where R R and R each represents an aromatic radical containing 1 to 2 aromatic siX-membered rings, or heterocyclic radicals containing a single fivemembered or six-membered heterocycle and at least one of the radicals R R R is heterocyclic. Thus, for example, in the acylhydrazines of the Formula 2, R and R may be benzene, diphenyl, naphthalene, pyridine, furan or thiophene radicals, while R is a benzene, furan or thiophene radical, but at least one of these radicals must be heterocyclic. From the foregoing it will be readily realized what the preferred constitution of the thiadiazoles of the Formula I is.

The diacylhydrazines of the Formula 2 containing a single hydrazine radical (n=l) are advantageously prepared by diacylating hydrazine hydrate or a suitable hydrazine salt, such as hydrazine sulfate, with a halide, preferably the chloride, of a heterocyclic monocarboxylic acid, or by first monoacylating such a hydrazine compound with an ester of a monocarboxylic acid and then further acylating the monoacylhydrazine with a halide of another monocarboxylic acid, for which purpose there are to be used the derivatives of two different heterocyclic monocarboxylic acids or one derivative each of a heterocyclic' monocarboxylic acid and of an aromatic monocarboxylic acid. In this manner there are obtained in the first case symmetrical and in the second case asymmetrical diacylhydrazines.

Acylhydrazines of the Formula 2 containing two hydrazine radicals (n=2 )are obtained when hydrazine is acylated in the molecular ratio of 2: 1:2 on the one hand with a dicarboxylic acid ester and on the other with a monocarboxylic acid halide. Thus, for example, 2 molecular proportions of hydrazine may be converted with 1 molecular proportion of a dicarboxylic acid derivative into a compound of the formula where X represents a hydrogen atom, or an alkyl group with 1 to 4 carbon atoms, or an alkoxy group with l to 4 carbon atoms, or a halogen atom such as bromine or preferably chlorine, or a phenyl radical, such as 2-, 3- or 4-methylbenzenecarboxylic acid, 2-, 3- or 4-chlorobenzenecarboxylic acid, 2-, 3- or 4-bromobenzenecarboxylic acid, 4-tertiary butylbenzenecarboxylic acid, 2:4-dimethylbenzenecarboxylic acid, 3 :4-dimethy1benzenecarboxylic acid, 3 :5-dimethylbenzenecarboxylic acid, 2:4-dichlorobenzenecarboxylic acid, 3 :4-dichlorobenzenecarboxylic acid, 2-, 3- or 4-methoxybenzenecarboxylic acid, 2:4 or 2:5 or 3 :4-dimethoxybenzenecarboxylic acid, 2:4:5 or 3 :4:S-trimethoxybenzenecarboxylic acid, 2-, 3- or 4-ethoxybenzenecarboxylic acid, 2-methoxy-4- or S-methylbenzenecarboxylic acid, Z-methQXy-S-chlorobenzenecarboxylic acid, 2-ethoXy-4-methylbenzenecarboxylic acid, Diphenyll-carboxylic acid; Naphthalenecarboxylic acids such as Naphthalene-L or -2-carboxylic acid, 3-methoxynaphthalene-2-carboxylic acid; Pyridinecarboxylic acids such as pyridine-2-, -3- or -4- carboxylic acid; Furancarboxylic acids such as Furan-Z-carboxylic acid, 3 :4-dichlorofuran-2-carboxylic acid, 5-chlorofuran-Z-carboxylic acid; Thiophenecarboxylic acids such as Thiophene-Z-carboxylic acid, 3- or S-methylthiophene-Z-carboxylic acid, 3 :5 -dimethylthiophene-Z-carboxylic acid, S-chlorothiophene-Z-carboxylic acid.

As dicarboxylic acids whose halides are suitable for the manufacture of acylhydrazines containing two hydrazine radicals there may be mentioned:

Isophthalic acid,

4 pounds containing tertiary nitrogen atoms, for example such as contain pyridine rings, may also be quaternated. The new thiadiazoles may be used for example, as agents affording protection from ultra-violet rays, as op- 5 tical brighteners, as scintillators, for electrophotographic Terfapbthahc reproduction or as intermediates in the manufacture of 1:1 -d1phenyl-4.4 -d1carboxyl1c acid, dyestuffs Fuan'2:5'd1::arb.OXyhc i Unless otherwise indicated, parts and percentages are Throphene-Z.5-d1carboxyl1c acid, b 6i ht 3:4-dimethylthiophene-2:S-dicarboxylic acid. yw g r Example 1 As phosphorus sulfides suitable for the manufacture or the thiadiazoles there may be mentioned phosphorus hepta- 30 parts of phosphorus pentasulfide are stirred into 24.1 sulfide (P 5 phosphorus sesquisulfide (P 8 phosparts of N-benzoyl-N'-isonicotinyl hydrazine in 150 parts phorus trisulfide (P 5 and preferably phosphorus pentaby volume of pyridine, whereupon the reaction mixture sulfide (P 8 heats up. When the exothermic reaction has subsided, The reaction is preferably conducted in the presence of the temperature is adjusted within 30 minutes to 60 to a tertiary nitrogen base. It is of advantage to use a 65 C. The mixture is stirred for 1 hour at 60 to 65 'C., tertiary nitrogen base whose boiling point is not too low, then the temperature is raised to the refiuxing point withpreferably at least 100 C. such, for example, as N:N- in 1 hour, and the reaction mixture is stirred on for 15 diethylaniline or N:N-dimethylaniline. Particularly suithours at a gentle boil, then cooled to room temperaable are cyclic tertiary nitrogen bases such as quinoline ture. 50 parts by volume of ethanol and then 2500 parts and above all pyridine bases such as pyridine itself and or" ice water are added in several portions, and the Whole alkylpyridines containing lower alkyl radicals such as 2-, is neutralized with aqueous sodium hydroxide solution; 3- or 4-methylpyridine (picolines), ethylpyridines or mixthe resulting 2-[pyridyl-(4')] 5-phenyl-l :3z4-thiadiazole tures of such pyridine bases. of the formula In other respect it is of advantage to conduct the re- (5) S action with the use of a clear excess of phosphorus sulfide N/ over the theoretically required minimum amount of 2 atoms of sulfur required for the formation of a thiadiazole N-N ring and at least a sufiiciency of the tertiary nitrogen base so is suctioned off, washed with 2000 parts of cold water such that the reaction mixture forms at first a solution or and dried, to yield about 205 pal-ts (:362% f the at least a readily mobile Suspension In genemh the theoretical yield) of colorless, shiny flakes which melt at action is rather exothermic; it is therefore of advantage to 132 to 183 a 0 Three recl-ystanizations from ethanadd the phosphorus sulfide to the solution of the acylo1+Watr (2:1) yield about 95 parts (:41% of the hydrazme the tgrtlary base gradually at room P theoretical yield) of colorless, shiny flakes which melt ture and to apply external heat n1y When on addltlon of at 182 to 183.2 C. and in ultra-violet light display a very the phosphorus sulfide the reaction mixture no longer heats Weak blue fluorescence up by itself. To complete the reaction it is of advantage to maintain the mixture for a few hours longer at an AalyslS'-C13H9N3S' Molecular Welght: 23929- elevated temperature, fo example between 80 and 150 40 C., during which as a rule the thiadiazole formed will 0 H i N gradually separate out. On completion of the reaction this separation can be completed by adding water and, if de- Calculated, percent 6P 79 7-56 sired, a water-soluble organic solvent. Found percent 01 It is also possible to manufacture the acylhydrazines required as starting material in the present process from E absorpuon dloxane: )maxzwz carboxylic acid halides and hydrazine compounds in the (6:2L40O1'. presence of a tertiary nitrogen base and, Without intep The following table lists further 1:3:4-th1ad1azoles that mediate isolation, to react the resulting acylhydrazine with can be prepared as descnbeld t Y i yields refer to a phosphorus sulfide Thus, for example, in a tertiary the crude product. The aborev ations 1n the fluorescence nitrogen base, preferably a pyridine base, a symmetrical 50 column have tha folowmg slgmficance: or preferably asymmetrical diacylhydrazine may be pre- SS: very Weak W: White pared from a monoacylhydrazine with the aid of a car- S: weak 0: orange boxylic acid halide, which is then immediately followed M: medium G: yellow by the reaction with the phosphorus sulfide. 5 St: strong Gr: green The new thiadiazoles may also be further reacted, for 5 L: brilliant B: blue example sulfonated, nitrated or chlorinated. Basic com- H: light-colored V: violet No. Formula Yield Properties Analysis (mol. Wt.) in percent cence Calculated Found CH3 Colorless, very fine, felted C 66. 38 C 66. 23 307/20,400 S I needles. M.P.=l41.8-143.2 H 4.38 H 4. 52 241/2,300 Q (ethanol-water) 5:2. N 10.59 N 16.64 241/2, 300 s N O C- 70.9

ll ll (253.31) ss n S Small, colorless shiny flakes and C 66.38 C (56.36 310/22, 800 N/ p needles. h l.P.=1 67-l68. 6 H 4. 38 H 4,.134 7 g h) CH3 14.3 (ethanol-water) 5.2 N 16.59 N 16.45

N 253. 31) SS-B /H\ (EH3 C(ilIOIIEGSS, very fins needles. 0 09.12 C 69.02 312/24, 800 s N t Q-o-om 76.9 water) 168's (ethanol' iii 12 ii 121 N-N CH3 (295. 41) 58-15 Anal sis (mo1.wt. A /e No. Formula Yield Properties y 2133335- 111 percent cence Calculated Found CH3 S Colorless, very fine, shiny C 67. 39 C 67. 28 316/22, 500 needles. M.P.=l79.5181.5 H 4. 90 H 5.21 242/5, 900 9 fi- CH3 80.2 (ethanol-water) 3:1 N 15.72 N 15.92

N (267. 34) StB S l Colorless, very fine, shiny C 57.04 C 56. 99 298/21, 600 needles and flakes. M.P.= H 2.95 H 2.97 10 N fi 79.2 1482-150 (ethanol-water) 1:1. N 15.10 N 15.10

NN (273. 75) SS-B S Colorless, very fin felted shiny C 57.04 C 56. 93 309/24, 800 needles. M.P.=190.6192 H 2.95 H 2.94 11 N ([1 u- Cl 62.1 (ethanol-water) 5:2. N 15.35 N 15.22

N (273. 75) S-B S Colorless, fine, felted needles. 0 49.07 C 48.77 310/26, 800 M.P.=222223 (dioxane- H 2.53 H 2. 63 12.. -(IT (['T Br 81. 1 ethanol-water 3:322). N 13. 21 N 13.04

N-N (818. 21) SS-B Cl S Colorless, very fine, felted C 50. 66 C 50. 95 310/24, 200 needles. M.P.=173l74.6 H 2. 29 H 2. 25 302/24, 400 13 -(lill fl CI 82.5 (ethanol-dioxane-water 2:121). N 13.64 N 13.39

NN (308. S-B

0 CH3 5 Almost colorless, very fine, felted C 62. 43 C 62. 43 327/19, 800 needles. M.P.=l43144 H 4.12 H 4. BOO/17,000 14.-. N (H)- 92. 2 (water-ethanol) 4:1. N 15. N 15. 59

N-N (269. 33 St-WV 0 CH3 Colorless, very fine, felted C 62. 43 C 62.55 302/21,900 /S\ I negsfilles.1 111016512124 g 14. g 12.

e ano-wa er 5: 5. 15.-.-- N -o 0- 77.7

- [I ll (269.33) M-B N-N I S Colorless, fine, felted, shiny C 62. 43 C 62. 69 325/24,600 needles. M.P.=166.2167.4 H 4.12 H 4.13 16-.." N o o- OCHS 82.8 (ethanol-water) 3:1. N 15.60 N 15. 79

H I] (269.33) 1 L-B 0 CH3 Colorless, very small, shiny C 63. 58 1 C 63. 63 329/23,000 S needles. M.P.=-186.5 H 4.62 H 4. 50 Boat/16,400 (ethanol-water) 7:1. N 14.83 N 15. 07. 17 N o 0- CH3 e7 H H (283. 34) L-B 0 CH Colorless, fine, felted needles. 0 63. 58 C 63. 27' 335/16,800 s I M.P.=194195 (ethanol- H 4. 62 H 4. 74 297/16,200 Water) 2:1. N 14. 83 N 14.81 18..... N o 0 e7 II ll (283. 34) L-B 0 CH Pale yellow, shiny needles. C 55.35 C 55. 46 334/16,600 S M.P.=210.42l2.2 (clioxane- H 3. 32 H 3. 45 294/17,400 ethanol-Water 2:1:1.) N 13.83 N 13.60 19..- N C 56.7

(303. 78) SS-WB N-N 0 CH3 Almost colorless, very fine C 60. 18 C 60. 23 336/27,000 -S l needles. M.P.=212.4-213.4 H 4. 38- H 4. 44- (ethanol-water) 1:1. N 14.04 N 13.85 20..... N o o- OCH; 67.2

\: H II (299. 34) L-HB 0 CH Light yellow, felted needles. 0 '60. 18 C 60. 23 351/l2,800 S I M.P.=l8ll82 (ethanol- H 4.38 H 4. 52' 298/16,000 water) 1:1. N 14.04 N 13.79 21 C 49. 2

|| (299. 34) L-B Gr 0 CH Light yellow, felted needles. C 58. 34' -C 58. 27 330/19,800 S I M.P.=167-168 (ethanol-water) H 4. 59 H 4.70 258/ 9,900 2:3. N 12.76 N 12.65 22 C- .0 CH3 70. 5

[I H (329. 39 L-G Gr O CH:

Analysis (mol. wt.) nnux/ No Formula Yleld Properties Fluores- 111 percent cellce Calculated Found 0 0 11 Colorless, fine, felted needles. 0 64. 62 332/2l,900 M.P.=171172 (ethanol-Water) H 5.08 304 15,e00

s 4:3. N 14.13 i -CH 85.5 23 I\( O C 5 (297.39) SPB H II 3 Small colorless, shiny flakes. C 72. 35 O 72.10 325/30,000 M.I =241A242.8 (dioxane- H 4. 15 H 4. 16 Ge (3Q- 87. 8 water) 5:1. N 13. 32 N 13. 21

I I1 I (315. 40) L-B Almost colorless, very fine C 70. 56 C 70. G8 322/20,?00

crystals. M.P.=204.4-205.4 H 3.83 H 3. 81 285/18,700 S (dioxane-ethanol-water 2:1:1). N 14. 52 N 14. 32 275/l8,600 @C/ 85.4 (289. 37) M-HV II II 5 Small, almost colorless, shiny O 59. 98 O 60.16 292/20,700 flakes. M.P.=236.5238 H 3. 36 H 3. 41 u l E E 1 1 Example 2 parts of phosphorus pentasulfide are stirred into a mixture of 8.03 parts of N-benzoyl-N'-isonicotinylhydrazine and 75 parts by volume of NzN-dimethylaniline,

12 action mixture heats up. When the exothermic reaction has subsided, the temperature is raised within 30 minutes to 60 to 65 C., the mixture is stirred for 1 hour at 6065 C. and then raised within 1 hour to the refluxing point,

Whereu on the mixture heats u SH htl The tem 5 and the yellow reaction solution is stirred for 15 hours at ture is faised within minutes to 6( to 65 C., the inixa gentle boll and then cooled to room temperature ture is stirred for 1 hour at to C., the temperature Parts by volume i ethanol and .then 2500 parts of is then raised within 1 hour to 110 C. and the reaction Water i adided In several. portions 2 the .whole 18 mixture is Stirred for 12 hours at lloto 5 C The neutralized with aqueous sodium hydroxide solution. The reaction mixture is then cooled to room temperature, 10 z'fiuryl'a')]'5'Pheny1'1:3z4'thladlazole of the formula treated with 50 parts by volume of ethanol and 500 parts (53) -f H /S\ of water and finally neutralized with aqueous sodium hy- Hg droxide solution. The NzN-dimethylaniline is removed with steam and the residue is cooled to room temperature, suctioned Off Washed with Cold Water and dried Them 15 1s suctioned off, washed with cold water and drled. Yield: are obtained about 6.8 parts (=85.2% of the theoretical about Parts (?57% of the theoretlcal) of an almost yield) of 2 [Py1.idy1 1 4 thiadiazole of colorless, crystalline powder which melts at 107 to the Formula 5 in the form of a slightly greenish powder 107.6 C. After having been recrystallized five times which melts at 172.8 to 181 0. Three recrystallizations from ethatlol+water (312) It Lorms colorlfisf Shmy. from dioxane+water (1:1) yield about parts 20 needles which melt at 108.2 to 109.2 C. and in ultra- =51.4% of the theoretical yield) of pale-yellow, shiny 11016111511? dlsPlay Weak blue ijuorescence; flakes melting at 1845 to Analys1s.-C H ON S. Molecular weight: 228.28.

When the parts by volume of NzN-dimethylaniline are replaced by 75 parts by volume of quinoline, there 25 0 H N s are obtained about 6.5 parts (=81.5% of the theoretical yield of 2 i 1 (4') 5 h 1 1;3 ;4 thj di l Calculated, percent.-- 63.14 3. 54 12.28 14.05 which on recrystallization from dioxane+water 1:1) Foundpement 63'15 31 yield about 3.0 parts (=37.6% of the theoretical yield) of almost colorless, shiny flakes melting at 176.5 to 30 Ultra'vlolet absorpnonm dloxane' )maxznl 182.4 C. (e=30,700)

Example 3 t The following table lists further 1:3 :4-thiadiazoles that 15 parts of phosphorus pentasulfide are stirred into a can be prepared as described above. The yields refer to mixture of 11.5 parts of N-furoy l-N'-benzoyl-hydraz1ne the crude product. For the significance of the abbreviaand parts by volume of pyridine, whereupon the retions in the fluorescence column see Example 1.

A 1 1. t. in... NO Formula Yield Properties Ha ysls (mo W Flume;-

in percent cence Calculated Found HC C}1 3 Almost colorless, very fine, C 64. 44 C 64. 54 324/27,900

H H shiny crystals. M.P.=110.l H 4.16 H 4.09 54 Ho 0-0 0 CH3 81 110.3 (ethanol-water) 1:1. N 11. 55 N 11.73

HC--CH s CH A1mtl1,h' dl. O6.

n u I a lVI. l ?8 8 9 .6 (39 1 15181 as H 5.3? 1% 5.23 324/2830 55.-." HO\ /C(% (|T -(|3CH3 40.1 water) 5:3. N 9.85 N 9.84

o N--N CH5 (284. 39) 8-13 3 c1 19 h 11 M.P.= c 4.85 H u l l iil ffi t t li ilol ivatcr) H 2.09 51 2 325/27'800 55..." o c 01 97.4 3:1. N 10 66 N 10.02

\ II II (202.73) SB 01 v, 1111,11 flk.C4.' 3. HO CH 1 3271 21558328 8612 5501 es H 3.83 E 3.3%

H ll water) 4:1. N 9.43 N 9.27 57-. HC\ /ocfi (fi- Cl 89.9 (297.18) SS-B OCH 0 1 1 li dl 0 BC on S 12525112148 2.8215? e 3.33 ii 3.33 58 g Il 54 3 Water) 1:1. N 10.85 N 11.11

m" l ll (258.31) SWB HO OH s .41 t 11 ,fltd 1. 0 0,

H H I l/[ 915 l6 f fO3F1 (et1z?0f- H 3. 1% 2.1 ago/30500 59---" H /0(fi 0 CH3 93.7 water) 1:1. N 10.85 N 11. 05

0 N (258. 31) S-WB HC-CH s V ry small 1 1 hi 0 71.03 0

iie es. 1v?1 1 7 0j;-1 7 H 3. 97 H i. 33432100 60.. HG\ /C([? 84 (dioxane-water) 5:2. N 9.20 N 9.08

o NN (304. 38) St-B Pale-yellow, shiny flakes. C 69.04 C 69.15 333/20,400 M.P.=141.8-143.4 (dloxane- H 3. 02 H 3.55 293/15,s00 no] N /s\ water) 5:3. N 10.07 N 10.18 s1 HO\ /C-(||J fi 68.2 (278.34) ss-WB Analysis (mol. wt.) Min/e N0. Formula Yield Properties Fluoresin percent cence Calculated Found HO CH S Colorless, very fine, felted C 57. 63 C 57. 65 323/22,800

g H needles. M.P.=175.4l76.6 H 3.08 H 3. 62 H /O- fi IO 66. 9 (ethanol-water) 2:1. N 18. 33 N 18.40

0 N l i (229. 27) S-B HC-OH S HCOH Pale-yellow, Very fine, felted C 55.04 C 54. 89 332/24,200

g g A g needles. M.P.=117.6ll8.4 H 2. 77 H 2. 56 63 H (l.| (ll- 74. 3 (ethanol-water) 1:3. N 12. 84 N 12. 78

O Nl i O (218. 24) SS-B C1 C1 Pale-yellow, shiny flakes. C 48. 50 C 58. 31 323/25,800 I A M.P.=165165.6 (dioxane- H 2. 04 H 1. 76 (IJ'1 /S\ 8 water) 2:1. 18597 figsfi N 9.42 11 0 N- l i' C1 C1 Pale-yellow, Very fine, felted C 43. 46 C 48. 58 326/28,800 needles. M.P.=219219.8 H 1. 52 H 1.35 /S\ 69 (dioxane-water) 6:1. 31 23515 N 8.59 SS G B I .5 r 4% O N N Cl 01 Light-yellow very fine, felted C 47. 72 O 47. 84 334/29,800

I I needles. M.P.=185.6-l86 H 2. 46 H 2. 50 ("3 (fi S\ (dioxane-water) 3:1. N 8. 56 N 8. 70 as--- HO\ o- --0 on. 71.5 s27. SS-GrB O NN C1 C1 Almost colorless, very fine, felted O 44.31 C 43. 89 323/24,400 I 1 needles. M.P.=162.6l64.6 H 1. 69 H 1. 70 C s (ethanol-water) 5:2. N 14.09 N 13. 99 C H II (298. 16) s-B 67...... HC\ /O--(3 (J 56. 4

o N N *N 01 Cl Cl 01 Light-yel1ow, very fine, felted C 33. 74 O 34.03 MS/29,500 needles. M.P.=229.8230.7 H O. 56 H 0. 59 337/29,600 fil H /S\ (dioxane-water) 3:1. N 7.87 N 8.02 68.--" C\ /C ("J O\ /CH 86.7 (356. 04) L-B Gr Example 4 is suctioned ofl, washed with much cold Water and dried.

7.1 parts of thiophene-Z-carboxylic acid hydrazide are stirred in 100 parts by volume of pyridine and then cooled below 5 C. 7.73 parts of para-methylbenzoylchloride are thenadded dropwise at O to 5 C., and the Whole is stirred for minutes at 0 to 5 C. and then for 45 minutes longer at room temperature. In the course of 1 hour the pale-yellow reaction solution is heated to 80 to 85 C. and then stirred for another 3 hours at this temperature. The solution is cooled to room temperature and treated with 15 parts of phosphorus pentasulfide, whereupon the reaction mixture heats up. When the exothermic reaction has subsided, the temperature is adjusted to 60 C. and the mixture is stirred for 1 hour longer at 60 to 65 C. The temperature is finally raised within 1 hour to the refluxing point, and the yellow reaction solution is stirred for 12 hours at a gentle boil, and then cooled to room temperature. parts by volume of ethanol and then 2500 parts of ice Water are added in several portions and the whole is neutralized with aqueous sodium hydroxide solution. The 2- [thienyl- (2) ]5-[4"-methylphenyl-(1") ]-1 :3 :4-thiadiazole of the formula The yellowish crude product is recrystallized from ethanol-l-water (2:1) with the aid of active carbon. Yield: about 7.8 parts (=60.5% of the theoretical) of a pale-yellow crystalline powder which melts at 136 to 137.2 C. Two recrystallizations from ethanol-l-water (2:1) yield 6.5 parts (=50.4% of the theoretical yield of pale-yellow, shiny flakes which melt at 137.2 to 138 C. and display in ultra-violet light pale-blue fluorescence.

Analysis.C H N S Molecular weight: 258.36.

21,100 x =270 mp 625100 The following table lists further 1:3 :4-thiadiazoles that can be prepared as described above. The yields refer to the crude product after one recrystallization. The abr breviations in the fluorescence column have the same significance as in Example 1.

Analysis (mol. wt.) 1 /e No. Formula Yield Properties Flfi iesin percent cence Calculated Found CH Almost colorless, very fine, felted C 54.80 C 54. 73 341/25,900

I needles. M.P.=168169 H 3. 61 H 3. 37

/S\ (dioxane-Water) 6:5. N 9.13 N 9. 23 85..." 1130- o-o o c1 71. s s. as) St-Gr-B II I! S NN CH Light-yellow, shiny needles. C 49. 27 O 49. 345/26,500 O1 M.P.=170.8171.4 (ethanol- H 2. 95 H 2.94 270/7,700 HC S I dioxane-water 9:3:1). N 8. 21 N 8. 18 II A l 86.- HaO-O\ fi- C1 72. 2 (341. 30) S-B Gr S rl N CH Colorless, shiny needles. 0 59. 57 C 59. 73 341/29,700 MP. =170.817l.6 (dioxane- H 4. 67 H 4. 71 278/7,100 H S ethanol-water 1:1:1). N 9. 26 N 9. 28

g g 87 H3O (l?- O OH; 86.1 (302. 43) S-B S NN 0 CH Weakly beigebr0wn shiny, C 60.73 C 60. 94 348/27,100 H S felted needles. M.P.=139.2 H 5.10 H 5.05 270/6,200

(Li H 139.6 (methanol-Water) 1:1. N 8.85 N 8.63 H3C 6 20 are ss G s NN CH3 Pale-yellow, very fine, felted O 57.81 C 57. 82 347/29,400 0 CH3 needles. M.P.=182-182.5 H 4. 85 H 4. 67 275/6,400 S\ l (dioxane-water) 1:1. N 8. 43 N 8. 45 89 H3CO\ /Ofi (ITQOCHs 66.8 (332. 45 L-GrB S NN CH Pale-yellow, finely crystalline C 54. 94 C 55. 13 345/26,500 I powder. M.P.=142.8144.2 H 3. 84 H 3. 95 278/5,700 HOO S HOOH (methanol-water) 2:1. N 10.68 N 10. 67 II II H H s 24. 44 s 24. 00 90. H3CO\ /C-CH1 fi-(J\ /CH 87. 7 (262. 36) S-GrB S NN 0 Example 5 10.2 parts of the diacylhydrazine of the formula IIC CH O O I all LK c oom s NHHN (which can be prepared by reacting 1 molecular proportion of 3:4-dimethoxybenzoyl chloride with 1 molecular proportion of thiophene-Z-carboxylic acid hydrazide in pyridine) in 100 parts by volume of 4-picoline are treated with 15 parts of phosphorus pentasulfide, whereupon the reaction mixture heats up. When a temperature rise can no longer be observed, the temperature is raised within 15 minutes to 60 to 65 C. The mixture is stirred for 1 hour at 60 to 65 (3., the temperature is raised within 1 hour to the boil and the yellow reaction solution is stirred for 12 hours under a slight reflux, during which the reaction product gradually crystallizes out. The whole is cooled to room temperature, parts by volume of ethanol and then 2500 parts of ice Water are added in several portions, and the whole is finally neutralized with aqueous sodium hydroxide solution. The product is suctioned off, washed with cold Water and dried, to give a yield of about 8.05 parts (=79.4% of the theoretical) of 2-[thienyl (2')] 5 [3:4" dimethoxyphenyl (1")] 1:3:4-thiadiazole of the formula HO--OH s I Hi l (%C C-OOHa S an.

in the form of pale-yellow fine crystals which melt at 155.6 to 156.8 C. Three recrystallizations from ethanol-l-Water (3:4) produce very fine, pale-yellow needles melting at 158.8 to 159.1 C. which in ultra-violet light display weak blue fluorescence.

Analysis.C H O N S Molecular weight: 304.40.

I C H l N Calculated, percent 55. 24 3. 97 9.20 Found, percent 55. 29 3. 88 9. l2

Ultra-violet absorption in dioxane: k =342 m 26,800).

When the 10 parts of phosphorus pentasulfide are replaced by 15 parts of phosphorus trisulfide, the yield amounts to about 7.0 parts (=69.1% of the theoretical) of 2 [thienyl (2')] 5 [3":4" dimethoxyphenyl- (1")]-1:3:4-thiadiazole which after four recrystallizations from ethanol-I-water (1:1) forms a pale-yellow Analysis (mol. wt.) )u-nnx/E No. Formula Yield Properties Fluoresin percent cence Calculated Found HO OH S Colorless, very fine needles. 58. 99 C 59. 06 326/23,300 1 M.P.=134.9135.4 (ethanol- H 3. 30 H 3.31 ass 7,200 93. HO 0- 0G 90.4 Water) 1:1. N 11.47 N 11.22

\ H II (244. 32 M-B CH Light-yellow shiny needles. 0 57. 11 O 57. 18 348/25,20O M.P.=163.2165.2 (ethanol- H 4.06 H 4.00 268/6,400 -C S water) 2:1. N 15.37 N 15.07

[I 98 (273. 39) M-B Gr 94 CHaC\ /C([? fills N N N CH Pale-yellow, very fine, felted C 57. 11 C 56. 81 Mil/23,100 needles. M.P.=l33.2l35 H 4. 06 H 4. 61 273/6,800 C C (ethanol-water) 1:2. N 15. 37 N 15. 35 H II (27s. 39) M-B Gr 95..- HaCC\ /C H fil- 86 s N N Example 6 (1") 1:3"::4 thiadiazolyl (2)1 furan of the formula 13.07 parts of the bis-diacylhydr'azine of the formula 0 (97) s s @r \h it 741 N .i 0 an O 0 0 in the form of a yellow powder which melts at -8 to 265 c-( i i l-0 \C- C. Yield after three reerystallizations from ortho-dichlob 84 t(6497fhth t'l)fl r0 enzene: pars 00 t e eoreica 0 ye- NHHN O NH EN 10w, very fine, felted needles which melt at 264 to 265 C. and display in ultra-violet light strong yellow fluores- (which can be prepared by reacting 2 molecular propor- 11 6- tions of benzoylchloride with 1 molecular proportion of Analysis C20HmON4S2 Molecular i 3 4 furan-ZzS-dicarboxylic acid dihydrazide in pyridine) in 150 parts by volume of pyridine are treated while being stirred O H I N with 20 parts of phosphorus pentasulfide, whereupon the reaction mixture heats up. When the temperature rises 40 Calculated percent 61.84 3 u 14 42 no longer, the reaction mixture is raised to the boil within Found, percent--- 61.73 3112 14120 2 /2 hours. The solution, which is now clear, is stirred for 20 hours at a gentle boil, during which the reaction Ultrawiolet absorption dioxane: Amx :374 m (6 product gradually crystallizes out. The whole is cooled =38,400); A =365 m =38,6(]()); z299 to room temperature, parts by volume of ethanol and 45 =17,2()0) then 9 P f of Water are f in evefa1 Portions, f The following table lists durther 1:3:4-thiadiazoles that the mutture 1s finally neutralized withaqueous sodium can be obtained as described above. The yields refer to hydroxide solution. The product is su'ctioned oil, Washed the crude product. Owing to the sparing solubility of the with cold water and then with hot water and dried. Yield: compounds concerned, the e-values marked are unreabout 12.9 parts 190% of the theoretical) of 2-[5'- 5 liable. The abbreviations in the fluorescence column have phenyl (l)-1:3':4-thiadiazolyl (2')] 5 [5" phenylthe same significance as in Example 1.

N0. Formula I Yield Properties Analysis (moi. Wm in percent cence Calculated Found H30 Pale-yellow crystalline powder. 0 63.44 C 63. 22 375/3100!) s M.P.=215218(ohl0ro- H 3.87 H 3.87 see/37,000 98 Q benzene). N 13.45 N 13.35 301717400 H II (416. 5a St-GrG CH3 H%--$[3H /s\ fii r@ O NN S Pale-yellow crystalline powder. 0 63. 44 C 63.16 378/37,G00 M.P.=288291(o-dichloro- H 3.87 H 4.24 ISM/38,000 99..." H c 'fi fi 100 benzene). N 13. 45 N 13. 42 ans/19,400 N-N (416. 53 L-G Hfifil-r s c c-o c cm II I] O NN Analysis (mol. Wt.) max/6 N0. Formula. Yield Properties Fluoresin percent cence Calculated Found HO O S HCCH S HCCI'I Yellow, finely crystalline powder. 47. 98 C 47. 84 392/37,500 1 n H u M.P.=265267 (o-dichloro- H 2.01 H 1. s1 3s1/3aeoo 108 HO 0-0 0-0 C-C OH 89.2 benzene). N 13. 99 N 13.98 332/20,500 ll ll II [I (400.53) S-(} S N-N O N-N S Example 7 thiadiazolyl (2')] [5" phenyl 1")-1":3":4"-

O HO

S N H-HN (which can be prepared by reacting 2 molecular proportions of benzoyl chloride with 1 molecular proportion of thiophene-2:S-dicarboxylic acid dihydrazide in pyridine) in 150 parts by volume of pyridine, whereupon the reaction mixture heats up. When a rise in temperature can no longer be observed, the reaction mixture is raised to the boil Within 3 hours and then stirred on for 18 hours at a gentle boil, and then cooled to room temperature. 50 parts by volume of ethanol and then 2000 parts of water are added in several portions and the whole is neutralized with aqueous sodium hydroxide solution. The product is suctioned off, washed with cold and then with hot water and dried. The crude product is then recrystallized from 350 parts by volume of ortho-dichlorobenzene with the aid of active carbon. Yield: about 4.6 parts (=68.3% ofthe theoretical) of 2-[5-phenyl-(1")-1:3':4-

thiadiazolyl-(2")]-thiophene of the formula 110 s\ HC---(HJH s QC o-d o-o c as s 11-11 Q in the form of a light-yellow powder which melts above 300 C. After recrystallizing it twice from ortho-dichlorobenzene it forms a light-yellow, finely crystalline powder which displays yellow fluorescence in ultra-violet light.

Analysis.C H N S Molecular weight: 404.5 48.

I C H N S Calculated, percent 59. 38 2. 99 13. 85 23. 78 Found, percent; 59. 20 3. 10 13.87 23. 81

Anal sis moLWt. 7m. N Formula Yield Properties y Flugi e sin percent cenee Calculated Found H O Yellow, shiny, short needles. 0 61.08 C 61. 04 379/37,000 S 1\/I.P.=29l.2-292 (o-dichloro- H 3.73 H 3. 74 370/38,500 benzene). N 12.95 N 12.97 270/10,000 111.... C C (432. M-G

1] ll N-N CH3 i ii C H Q S N-N S Golden-yellow, short, felted C 61.08 C 60.94 385 26,500 needles. M.P.=above 300 H 3.73 H 3.70 +375421000 112.. 1130- C C- 624 (trlchlorobenzene). N 12.95 N 12.81 +272/8,500 It I] (432. 60) St(} HCCH S H H C CC C- CHa S NN H3O s Small yellow shiny flakes. C 65.08 C 65. 04 384 40,500 M.P.=above 300 (u-diohloro- H 5. 46 H 5. 43 375440300 113 H C(I7- --("J ?IJ 59 benzene). N 10.8 N 10.84 275/11,500

516." H3O N N 16) St G HCCH S OH: I] II l (3 C0 0 C-GH;

\ u n l S NN CH:

H O Brilliantly yellow, fine, felted O 62.58 C 62. 48 +380/28,000 l /S\ neeidlelsl. I\g.P.=al))0ve 300 4.38 H 4.67 +371/29,000 0- 1c oro enzene. 12.16 N 12.45 +275 10,500 114-." H C- -(I !J (H1-- 62 (460.66) StG CH; HCCH S l ll 11 0 C0 C- CH ll ll S NN 2? Example 8 20 parts of phosphorus pentasulfide are stirred into 12.73 parts of the bis-diacylhydrazine of the formula (which can be prepared by reacting 2 molecular proportions of furoylchloride with 1 molecular proportion of terephthalic acid dihydrazide in pyridine) in 150 parts by volume of pyridine, whereupon the reaction mixture heats up. When a temperature rise can no longer be observed, the reaction mixture is raised within 2 /2 hours to the boil and stirred for another 20 hours at a gentle boil, and then cooled to room temperature. 50 parts by volume of ethanol and then 2000 parts of water are added in several portions and the whole is neutralized with aqueous sodium hydroxide solution. The product is suctioned 01f, washed with cold and then with hot water and dried. Yield: about 12.4 parts (=98.1% of the theoretical) of 1-[5'-furyl-(2"') 1':3:4' thiadiazolyl (2')] 4 [5"- furyl-(2)-1":3":4-thiadiazolyl-(2")]-benzene of the formula AnaZysz's.C H O N S Molecular weight: 378.44.

C H N Calculated, percent 57.13 2, 66 14 81 Found, percent 57.18 2. 86 14. 89

Ultra-violet absorption in dioxane:

Example 9 A polyacrylonitrile fabric, for example Orlon, is treated at a goods-to-liquor ratio of 1:40 with 0.1% of 2- [pyridyl- (4' 1 -5- [4"-tertiary butylphenyl-( 1") ]-1 :3 :4- thiadiazole of the Formula 8 for 1 hour at about 70 to 97 C. in a bath which contains per liter 1 gram of formic acid of 85% strength, and then rinsed and dried. The fabric treated in this manner has a higher white content than the untreated material.

When the 2-[pyridyl-(4')]-5-[4"-tertiary butylphenyl- (1")]-1:3:4-thiadiazole is replaced by an identical amount of the 2-[pyridy1-(4')]-5-[3":4"-dimethylphenyl-(1")]-1:3:4-thiadiazole of the Formula 9, a similar optical brightening eifect is obtained.

Example 10 Films about 40 thick are made from a 10% solution in acetone of acetylcellulose containing, calculated on acetylcellulose, 1% of 2-[3:-5-dimethylthienyl-(2')]-5- [4-"-tertiary butylphenyl-(l)]-113:4-thiadiazole of the Formula 83 and of 2-[3:5'-dimethylthienyl-(2)]-5- [3:4"-dimethoxyphenyl-(1")]-1:3:4-thiadiazole of the Formula 89. After drying the following values of the 28 permeability to light are obtained (measured with a Beckmann-DU-spectrophotometer) 1:3:4thiadiazole of the formula Permeability to light -320-360 -320-380 m, 376. 5 390. 5 mp 379 393 my. 382. 5 396. 5 my 387. 5 400. 5 my 395 -405 ID What is claimed is: 1. A l:3:4-thiadiazole of the formula in which R is pyridyl and R is a member selected from the group consisting of OCH;

OCH: OCH;

0 CH3 0 on, 0 on,

- -O CH3 (|)CH3 0 C2115 2. A 1:3:4-thiadiazole of the formula in which R is a member selected from the group consisting of 29 30 i and R is a member selected from the group consisting in which R is furyl and R and R1 is each a member of selected from the group consisting of CH3 CH 01 OCH OCH;

0 CH 5 and -OCH3, and Q-wm O CH:

5. A 1:3:4-thiadiazole of the formula R1-O/ \C-R3O/ \CR3 3. A 1:3 :4-thiadiazole of the formula 1'11 ii in which R is thienyl and R and R is each a member 8 selected from the group consisting of R 0 \C R CH u 2 in which R is a member selected from the group con- 3 sisting of 1 l l I (EH5 5 CH3 :1 (lf-()H H("7--(I.| (H3113 (IJCHa HO 0 and HaC-C O and . I and R is a member selected from the group consistmg OCH f 3 )C]3'.s r

H ('11 ('31 Q 6. A 1:3:4-thjadiazole of the formula (3H3 in which R is phenyl.

7. A 1:3:4-thiadiazole of the formula 0011 HCOH s I k ii F 0 N-N in which R is phenyl. and 8. A 1:3:4-thiadiazole of the formula R1(]3/ o-R, Q 1r 1r in which R and R each is furyl. 9. A 1:3:4-thiadiazole of the formula 4. A 1:3 :4-thiadiazole of the formula 7 in which R is phenyl.

31 10. A 1:3:4-thiadiazo1e of the formula S R1"?/ ("3-Rz 1% N in which R is thienyl and R is pyridyl.

11. A 1:3:4-thiadiazole of the formula 32 References Cited in the file of this patent UNITED STATES PATENTS Trosken et a1 Dec. 6, 1955 Ainsworth Jan. 31, 1956 OTHER REFERENCES Oharbrier et aL: Bull. Soc. Chim., France, 1949, pp. 237-40.

Bambas: Heterocyclic Compounds (Interscience), 10 pp. 81-8 1952 McMillan et aL: J. Am. Pharm. Assoc., vol. 42. pp. 457-64 (1953).

Ohta et aL: J. Pharm. Soc., Japan, vol. 76, pp. 10-12 15 (1956).

IRVING MARCUS, Primary Examiner.

DUVAL T. MCCUTCHEN, WALTER A. MODANCE,

Examiners.

UNITED STATES PATENT OFFICE QERTIFICATE ()F CORRECTION Patent No, 3,178,440 April 13, 1965 Adolf Emil Siegrist et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 30, lines 35 to 40, the center radical should appear as shown below instead of as in the patent:

same column 30, lines 39 to 44, the right-hand radical should appear as shown below instead of as in the patent:

OCH

column 31, line 6, for "R" read R lines 12 and 19, for "R and R each occurrence, read R and R Signed and sealed this 12th day of October 1965.

(SEAL) Attest) ERNEST W. SWIDER EDWARD J BRENNER Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,178 ,440 April 13, 1965 Adolf Emil Siegrist et al.

It is hereby certified that'error appears in the above numbered patentrequiring correction and that the said Letters Patent should read as corrected below.

Column 30, lines 35 to 40, the center radical should appear as shown below instead of as in the patent:

OCH

same column 30, lines 39 to 44, the right-hand radical should appear as shown below instead of as in the patent:

OCH

column 31, line 6,for "R" read R lines 12 and 19, for I "R and R each occurrence, read R and R Signed and sealed this 12th day of October 1965,

(SEAL) Attest) ERNEST W. SWIDER A EDWARD J, BRENNER Attesting Officer Commissioner of Patents 

6. A 1:3:4-THIADIAZOLE OF THE FORMULA 